290 S. Vincent, 



together by their processes". And more recently^): "These pigmented 

 cells are mostly in the interior of the body". 



So that we have certainly two zones, a "cortical" and a "medullary" 

 in these bodies; the cortical is devoid of chromogenic cells, the 

 medullary consists almost entirely of them. The pigmentation in the 

 central cells is only seen after hardening in, or treatment With, some 

 fluid containing bichromate of potassium. 



On further examination too, it is clear that one must agree with 

 the view of Balfour that the cells in the outer layer are columnar. 

 This is depicted in PI. XVI. fig, 2. But, after all, the chief distinction 

 between the two kinds of cells is that those in the central portion 

 contain the characteristic chromogen of suprarenal medulla (Eberth, 30), 

 while those in the external layer do not. This distinction does not 

 seem to have been noted by Balfour.-) 



Undoubted nerve-cells are found included in the substance of 

 many of the paired medullary bodies, both in the "axillary hearts" 

 and those which follow, indeed in all, except perhaps a few of the 

 most posterior. But in addition to these there are to be seen, especially 

 in the axillary hearts, some cells as large as the nerve-cells, but 

 whose protoplasm has become stained brown with the potassium 

 bichromate. There are still other cells which are rather smaller, but 

 have the same characters. These I believe to he transition forms 

 hetiveen nerve-ganglion cells and the proper medullary cells of the 

 organ. Balfour [3] suggests the possibility that such cells might 

 exist, but was unable to determine their presence. 



It has been shown in previous communications [118, 120] that 

 these paired bodies really correspond physiologically to the medulla of 

 the suprarenal capsule of the higher Vertebrata. It has also been 

 demonstrated that the chromogen is of the same nature as in the 

 suprarenal medulla of higher animals [81]. 



The intimate relations which subsist between these paired bodies 



1) Birm. Med., Review. April 1898. p. 214. 



-) It may be that the physiologically active principle is secreted only by the 

 central (chromogenic) cells. It is of course impossible to settle this point by 

 direct experiment. 



